To write a successful critique, first find a good picture of the piece you wish to do and have it in front of you for reference. Also try to find a brief history/background behind the work, it will be useful for identification of parts during the critique.
Now on to the actual critique. The first section will be the Elements of Design. In this section there are subcategories: Line and Shape, Texture, Value, Color, and Space.
In Line and Shape, study the forms in the painting and the lines, and write
out any similarities and contrasts you see in the positioning of the lines,
i.e. are they parallel? Do they converge at a vanishing point? Does the vanishing
point have some kind of significance in the
composition? Etc. For shapes, are they organic or geometric? Do they create contrast?
In texture, examine the actual texture (i.e. that you would feel if you were allowed to touch the piece) of the work in question. Does it appear rough or smooth? Then examine the simulated textures, like cloth or wood, and comment on whether it is true to life, or unreal. Once again, state what contrasts the textures create.
For value, examine and state the location of the light source. This will usually be opposite to the brighter areas of the work. Is there something significant about where the lights and darks are? Which parts are the brightest or the darkest? You may also state where you can see all the transitions, such as highlight, umbra, shadow, and penumbra.
For color, if applicable, look at the color scheme and state what you think it is. Usually, it will be local color, but not always. And there are often color schemes within another, especially when it comes to objects that can be various colors, like clothing. State which parts are dull, and which parts are bright, and the significance of each. Also state whether the work is cool or warm, and if there is a heavier or lighter side.
For space, state whether it is infinite or limited. Infinite space is when you can see far into the distance. Limited space occurs when there is a wall or something in the work that makes the work have a shallow depth. State what creates a sense of depth in the work.
The second section is Principles of Design. In this section, the subcategories are: Harmony, Variety, Balance, Dominance and Center of Interest, and Economy.
In harmony, state what unifies the composition, i.e. repetition, color scheme, etc. Variety is the exact opposite. What creates interest in the composition, i.e. contrast?
How the objects are spaced out and arranged in a composition is called balance. There is symmetrical, where one side is exactly the same as the other; approximate symmetry, where things are balanced equally on both sides, but are not exactly the same; and asymmetrical, where there is no balance. Positive and negative space is important in this section.
Dominance and Center of Interest: Where is your eye drawn to when you look at the composition, and why?
Economy is using simple means to give a better composition or a more powerful image.